1. Field of the Invention
The present invention relates to an air conditioner for a vehicle, and more particularly, to an air conditioner for a vehicle that includes: a mode door having a thin, plate member, which slidably operates inside an air-conditioning case to control the degree of opening of a defrost, vent, a face vent and a floor vent, and a gear shaft, which engages with the thin plate member for operating the thin plate member; and constant discharging means disposed at a rail portion of the thin plate member and at a guide part of an air-conditioning case overlapped with the rail portion, so that air of a fixed quantity is discharged to side vents of the face vent.
2. Background Art
In general, an air conditioner for a vehicle is a car part, which is installed in a vehicle for the purpose of cooling or heating the interior of the vehicle in the summer season or the winter season or removing frost from a windshield in the rainy season or the winter season to thereby secure a driver's front and rear visual fields. Such an air conditioner typically includes a heating device and a cooling device together, so that it can heat, cool or ventilate the interior of the vehicle through the steps of selectively introducing the inside air or the outside air into the air conditioner, heating or cooling the introduced air, and blowing the heated or cooled air into the vehicle.
According to mounted structures of a blower unit, an evaporator unit and a heater core unit, such an air conditioner is classified into a three-piece type air conditioner where the blower unit, the evaporator unit, and the heater core unit are disposed independently, a semi-center type air conditioner where the evaporator unit and the heater core unit are embedded in an air-conditioning case and the blower unit is mounted separately, and a center-mounting type air conditioner where the three units are all embedded in the air-conditioning case.
Recently, an independent type air conditioner, which separately and independently provides air of different temperatures to a driver's seat and to a passenger's seat inside the vehicle to thereby individually heat and cool the seats according to the driver's or the passenger's need, has been disclosed.
FIG. 1 illustrates the semi-center type air conditioner. In FIG. 1, the air conditioner 1 includes: an air-conditioning case 10 having an air inflow port 11 formed on an inlet thereof and a defrost vent 12a, a face vent 12b and floor vents 12c and 12d mounted on an outlet thereof in such a way as to be adjusted in degree of openings by mode doors 16; a blower (not shown) connected to the air inflow port 11 of the air-conditioning case 10 for sending inside air or outside air; an evaporator 2 and a heater core 3 that are mounted on air passageways in the air-conditioning case 10; and a temperature-adjusting door 15 mounted between the evaporator 2 and the heater core 3 for adjusting the degree of opening of a cold air passageway P1, which bypasses the heater core 3, and a warm air passageway P2, which passes through the heater core 3.
Furthermore, the floor vents 12c and 12d are divided into a floor vent 12c for a front seat and a floor vent 12d for a rear seat.
In addition, the face vent 12b includes a center vent for discharging air toward the center of the inside of the vehicle, and side vents formed at both sides of the center vent for discharging air toward both sides of the inside of the vehicle.
Moreover, the temperature-adjusting door 15 and the mode doors 16 respectively include rotary shafts 15b and 16b rotatably mounted on both sides of the air-conditioning case 10 and plates 15a, 16a and 16b formed at one side of the rotary shafts 15b and 16b. In this instance, for the mode door 16, a center pivot door having the plates 16a and 16c formed at both sides of the rotary shaft 16b may be used.
The temperature-adjusting door 15 and the mode doors 16 are respectively connected to a cam (not shown) or a lever (not shown), which is actuated by an actuator (not shown) mounted on an outer surface of the air-conditioning case 10, and rotatably operated to thereby adjust the degree of opening of the cold and warm air passageways P1 and P2 or open or close the vents 12a to 12d. 
According to the air conditioner 1 having the above structure, in the case of the greatest cooling mode, the temperature-adjusting door 15 opens the cold air passageway P1 and closes the warm air passageway P2. Accordingly, the air blown by a blower (not shown) is converted into cold air by heat-exchanging with refrigerant flowing inside the evaporator 2 while passing through the evaporator 2, and then, flows toward a mixing chamber (MC) through the cold air passageway P1. After that, the converted air is discharged to the inside of the vehicle through the vents 12a to 12d opened by a predetermined air-conditioning mode, whereby the inside of the vehicle is cooled.
Moreover, in the case of the greatest heating mode, the temperature-adjusting door 15 closes the cold air passageway P1 and opens the warm air passageway P2. Accordingly, the air blown by the blower (not shown) passes through the evaporator 2, is converted into warm air by heat-exchanging with cooling water flowing inside the heater core 3 while passing through the heater core 3 through the warm air passageway P2, and then, flows toward the mixing chamber (MC). After that, the converted air is discharged to the inside of a vehicle through the vents 12a to 12d opened by the predetermined air-conditioning mode, whereby the inside of the vehicle is heated.
In the meantime, in the case of not the greatest cooling mode but a half cooling mode, the temperature-adjusting door 15 is rotated to a neutral position, and opens all of the cold air passageway P1 and the warm air passageway P2 relative to the mixing chamber (MC). Accordingly, the cold air passing through the evaporator 2 and the warm air passing through the heater core 3 flow toward the mixing chamber (MC) and are mixed with each other, and then, are discharged to the inside of the vehicle through the vents 12a to 12d opened by the predetermined air-conditioning mode.
Furthermore, there are three mode doors 16 for opening and closing the defrost vent 12a, the face vent 12b and the floor vents 12c and 12d. In this instance, as shown in FIG. 2, in the case of the mode door 16 for opening and closing the face vent 12b, the plate 16c for opening and closing the side vent of the face vent 12b is formed so small as not to completely close the side vents, so that air of a fixed quantity is discharged to the side vents of the face vent 12b without regard to any air discharge mode in order to defrost windows of the vehicle.
However, in order to constantly discharge air of a fixed quantity to the side vents of the face vent 12b, the plates 16c formed at both ends must be formed smaller than the plate 16a formed at the center of the mode door 16.
Additionally, in the case that the three mode doors 16 are mounted to open and close the defrost vent 12a, the face vent 12b and the floor vents 12c and 12d, there is no problem because only the end plates 16c of the mode door 16 for opening and closing the side vents of the face vent 12b is formed smaller.
In addition, in the air conditioner using one or two mode doors in order to open and close the defrost vent 12a, the face vent 12b and the floor vents 12c and 12d, in the case that the end plates 16c of the mode door are formed smaller, it causes a deterioration in air-conditioning performance because air of a predetermined amount leaks toward the defrost vent 12a or the floor vents 12c and 12d. 